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Biomedical subjects

A M Shah

Publications and source records attributed to A M Shah.

At least 109 records · Page 6Linked to original sources
PubMed1989

Inotropic effects of endothelin in ferret ventricular myocardium.

The characteristics of the inotropic response to endothelin were studied in isolated ferret papillary muscle preparations. Endothelin (0.1-10 nM) induced concentration-dependent positive inotropic effects. At 10 nM, isometric tension increased by 17%, maximum rate of tension development by 18%, maximum velocity of unloaded shortening by 23% and peak isotonic shortening by 11%. Time to peak isometric tension and half isometric relaxation time were unaltered by endothelin. This pattern of change is similar to that of elevating extracellular calcium concentration.

Animals↗
PubMed1989

Endocardium modulates myocardial inotropic response to 5-hydroxytryptamine.

The endocardium modulates contractile performance of subjacent myocardium in isolated heart muscle. We investigated the effects of 5-hydroxytryptamine (5-HT, 0.01-30 microM) on isolated cat papillary muscles with or without intact endocardium (+E or -E, respectively). Selective endocardial damage by 1-s immersion in 1% Triton X-100 caused reduction in half-isometric relaxation time (RT1/2) and isometric twitch tension (TT), but not maximum unloaded shortening velocity (Vmax). 5-HT caused reduction in RT1/2 in endocardium-intact but an increase in endocardium-damaged preparations (at 30 microM: -12.1 +/- 1.8%, +E; +5.2 +/- 1.5%, -E). Mean percent increases in TT were greater in endocardium-damaged muscles (at 30 microM: 37.3 +/- 8.6%, +E; 107.3 +/- 19.5%, -E). In the presence of ketanserin (1 microM), 5-HT reduced RT1/2 in endocardium-intact (at 30 microM: -11.9 +/- 1.3%) but not endocardium-damaged muscles (except slightly at 30 microM) and increased TT at 30 microM by 28.7 +/- 4.9% (+E) and 48.9 +/- 15.6% (-E). In the presence of propranolol (1 microM), 5-HT increased RT1/2 (+E and -E) while increasing TT by 23.3 +/- 7.8% (+E) and 43.5 +/- 2.5% (-E). Endocardium did not influence changes in Vmax. Ketanserin (1 microM), but not propranolol (1 microM), markedly diminished endocardial damage induced by 5-HT (greater than or equal to 10 microM). These results suggest a 5-HT-induced endocardium-mediated "inhibitory" effect (causing earlier isometric relaxation) that is not blocked by ketanserin.

Animals↗
PubMed1989

Myocardial inotropic responses to aggregating platelets and modulation by the endocardium.

Ventricular mural thrombi complicate many cardiac diseases. The endocardial endothelium can modulate the mechanical performance of subjacent myocardium and mediate responses to certain physiopharmacologic agents. We studied the effects of aggregating platelets on the contractile performance of isolated cardiac muscle. The role of the endocardium was investigated by selectively damaging it by very brief (1 second) exposure to 1% Triton X-100 in some muscle preparations before experiments. Cat papillary muscles (n = 54) were attached to an electromagnetic length-tension transducer in organ baths containing Krebs-Ringer solution (1.25 mM Ca2+, 35 degrees C), and stimulated electrically at 0.2 Hz. Homologous washed platelets (final concentration 3 x 10(11)/l) aggregated spontaneously on addition to baths. Mechanical performance increased significantly more in muscles with damaged endocardium than in intact muscles (p less than 0.05); total peak isometric twitch tension increased by 31.8 +/- 7.8% (with damaged endocardium) and 11.8 +/- 2.6% (with intact endocardium), and peak isotonic twitch shortening increased by 36.7 +/- 7.8% (with damaged endocardium) and 9.6 +/- 2.0% (with intact endocardium). Increases in maximum velocity of unloaded shortening were similar in both muscle groups. Time to half isometric twitch tension decline decreased in intact muscles (3.6 +/- 1.0%) but increased in Triton-treated muscles (2.5 +/- 1.3%, p = 0.003 for difference between groups). The inotropic response to platelets in muscles with intact endocardium was unaltered by pretreatment of muscles with indomethacin (10 microM) or by stimulation of platelet aggregation with thrombin (0.1 unit/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMedDate not supplied

Spectrum of pediatric urolithiasis in western India.

Of 1,211 patients with urolithiasis treated at this institution over a nine years period, there were 77 (6.4%) pediatric cases. The commonest age group was 6-10 years (55.8%). Male:female ratio was 7.6:1. Hindus constituted 72.7% of the patients. There was no significant seasonal variation. The commonest site was urinary bladder (67.5%). The upper: lower urinary tract stone ratio was 1:2.85. Majority belonged to the lower-middle or poor income groups having a cereal based diet with minimal or poor protein intake. The common constituents of stones were calcium (98.7%), oxalate (87%), phosphate (84.4%) and uric acid (76.6%). Of all these, uric acid had the richest concentration (grade of ++ or more) in 93.2%. Only 4 stones (5.2%) were "pure": calcium oxalate--3 and calcium phosphate--1; whereas 73 (94.8%) were mixed stones. Of these, 9 (11.7%) were "predominant" mixed stones, with only one constituent having rich concentration (grade of ++ or more) and all others being either trace or +. The rest 64 (83.1%) were "heterogenous" mixed stones having rich concentration of more than one constituent.

Child↗
PubMedDate not supplied

The cardiac endothelium: cardioactive mediators.

Endothelial cells within the heart release a number of substances that modulate myocardial contractile function. These agents include nitric oxide, endothelin, prostanoids, adenylpurines, and other substances that have so far been characterized only in bioassay studies. A notable feature of many of these agents is that they influence contractile behavior predominantly by modifying cardiac myofilament properties rather than altering cytosolic Ca2+ transients. A consequence of this subcellular action is often a disproportionate effect on myocardial relaxation and diastolic tone. The paracrine modulation of cardiac myocyte function by endothelial cell factors is likely to be an important mechanism contributing to the overall regulation of cardiac contractile function, both physiologically and in pathological states.

Animals↗
PubMedDate not supplied

Neonatal mydriasis due to effects of atropine used for maternal Tik-20 poisoning.

A neonate was born to a mother who had consumed an organophosphorus(OPC) compound with suicidal intent. The mother was administered atropine and this caused mydriasis in the neonate without any other pharmacological effects. There was no evidence of placental dysfunction. There are no case reports of OPC consumed in pregnancy and its effect on neonates or of effects of massive doses of atropine in the mother and its effects on the fetus or the newborn.

Atropine↗
PubMedDate not supplied

Non-invasive respiratory monitoring in paediatric intensive care unit.

Monitoring respiratory function is important in a Paediatrics Intensive Care Unit (PICU), as majority of patients have cardio-respiratory problems. Non-invasive monitoring is convenient, accurate, and has minimal complications. Along with clinical monitoring, oxygen saturation using pulse oximetry, transcutaneous oxygenation (PtcO2) and transcutaneous PCO2 (PtcCO2) using transcutaneous monitors and end-tidal CO2 using capnography are important and routine measurements done in most PICUs. Considering the financial and maintenance constraints pulse oximetry with end tidal CO2 monitoring can be considered as most feasible.

Capnography↗
PubMedDate not supplied

Vascular endothelium.

Endothelium lines all blood vessels and the cardiac cavities and has a central role in cardiovascular homeostasis. It releases several potent substances which mediate the control of vascular tone and cardiac contraction. Endothelial dysfunction is implicated in many disease states. Elucidation of the underlying mechanisms is likely to lead to novel therapeutic strategies.

Animals↗
PubMedDate not supplied

Lipomatosis of the ileocecal valve causing recurrent small bowel obstruction.

A case of lipomatosis of the ileocecal valve causing recurrent intestinal obstruction is described. Barium enema with air contrast provides an important diagnostic tool. If confirmed intraoperatively and by histopathologic examination on frozen section, limited resection of the ileum and cecum is advocated rather than blind right hemicolectomy.

Female↗
PubMedDate not supplied

Infantile mediastinal primary endodermal sinus tumour.

Primary extragonadal mediastinal endodermal sinus tumour is rare, and to date very few cases have been reported in the literature. We present here a case of rare extragonadal highly malignant commonest germ cell tumour in an infant who presented with a rapidly progressive mediastinal mass with dry non-productive cough, tachypnea without significant respiratory distress or toxicity.

Biopsy, Needle↗